This invention relates to novel oil separating vent systems for motorcycle engines, removing a major amount of lubricating oil droplets and mist from the crankcase breather airstream passing through the rocker box chamber as the airstream travels to the air cleaner.
By separating lubricating oil from the airstream propelled by descending pistons from the crankcase up to the rocker box, and diverting the oil for return to the crankcase, the advantages of conserving the oil and minimizing pollution by escaping oil are achieved at all times when the engine is running.
Conventional motorcycle engines offer inadequate separation of lubricating oil from the crankcase breather airstream, and the present invention performs this separation far more efficiently than conventional engines. Thus the objectives of the present invention are to conserve lubricating oil and minimize escaping oil pollution by enhancing the separation effectiveness of the engine itself in delivering the crankcase breather airstream and the separated oil back to the crankcase.
Conventional motorcyle engines normally direct the breather airstream from the crankcase through the rocker box, then to the air cleaner or filter receiving intake air for delivery to the carburetor. This air filter is externally exposed, and if oil entrained as fog or mist in the breather airstream is collected by the air cleaner, such oil accumulates, blocking the air cleaner and may drip outside the engine, collecting on the ground below or on the rider""s clothing.
The present invention employs a zig-zag labyrinth path for conducting the breather airstream carrying oil mist or fog and droplets of lubricating oil through the rocker box on its way to the air filter. As the oil mist coalesces into droplets, these droplets acquire momentum from the movement of the breather airstream carrying them, and at every change of direction in the zig-zag airstream path, momentum carries the droplets out of the airstream to be deposited on the separator labyrinth walls. These deposited droplets of lubricating oil then collect and descend by gravity toward the bottom of the labyrinth, where they are conducted by vents and drain ports directly to drain passages leading back to the crankcase oil sump.
Accordingly, a principal object of the invention is to maximize the separation of entrained lubricating oil from the moving crankcase breather airstream.
Another object of the invention is to collect this separated lubricating oil efficiently and return it directly to the crankcase.
A further object of the invention is to minimize the escape of lubricating oil from the engine via accumulation in the air filter.
Still another object is to minimize the traces of accumulated oil in the intake air delivered to the carburetor for combustion, which thereby avoids contributing burned oil to the engine""s exhaust.
Other objects of the invention will in part be obvious and will in part appear hereinafter.
The invention accordingly comprises the features of construction, combinations of elements, and arrangements of parts which will be exemplified in the construction hereinafter set forth, and the scope of the invention will be indicated in the claims.